<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>event4</title>
<script src="js/vue.min.js"></script>
</head>
<body>
<div id="app">
  <button v-on:click="say('hi',$event)">say hi</button>
</div>

<script>
new Vue({
  el: '#app',
  methods:{
    say:function(message,e){
      alert(message);
      console.log(e.currentTarget);
    }
  }
})
</script>
</body>
</html>